Polish Rally Against Immigration

Highly nationalistic, highly Catholic, Polish people stand in stark contrast to many of their European neighbors when confronted with the prospect of Muslim immigration. Some might note that Jozef Pilsudski, who was a Polish war hero in the Soviet-Polish war of 1919-1921, was a favorite of Adolph Hitler. What is stopping nationalism from rearing it’s violent head in the face of a steady stream of incoming Middle Eastern migrants/refugees?